American football is the largest participation sport in U.S. high schools. Recently, many have expressed concern about the sport’s safety with some even calling for banning youth and high school tackle football. We recently published a study in JAMA Neurology suggesting that, in general, men who played high school football in 1950s Wisconsin did not have a higher risk of poor cognitive or emotional health later in life than those who did not play.

Recent concerns about football’s safety have been driven largely by reports of chronic traumatic encephalopathy (CTE) among retired professional players. CTE is a neurodegenerative disease thought to result from repetitive head trauma with symptoms including memory loss, aggression, confusion and depression. A recent study in JAMA reported evidence of CTE in 110 of 111 deceased retired NFL players who donated their brains for posthumous examination. This important study adds to a larger body of work linking repetitive sports-related concussion with neurodegenerative disease.

However, such research, which depends on brains donated by families of players many of whom were symptomatic before death, is not designed to establish the base rate of neurodegeneration among the larger population of football players. A critical question remains: what is the risk of later-life cognitive and emotional dysfunction for American high school football players?

In the absence of a randomized trial, the “gold standard” method for addressing this question is to follow a large cohort of individuals from adolescence to old age and measure many factors that, in addition to high school football participation, may influence long-term health. We used data from the Wisconsin Longitudinal Study (WLS), which has followed a random sample of Wisconsin class of 1957 high school graduates.

This dataset contains a rich set of baseline variables related to family background, adolescent characteristics (including IQ) and education. To control for baseline variables, we matched men who played football with non-players with similar baseline variables. We then compared the later-life cognitive functioning and psychological health of the matched football players and non-football players at ages 54, 65 and 72.

We were surprised to find that playing high school football did not have a statistically significant harmful effect on later-life cognition and mental health in this sample. Moreover, it did not have an effect on anxiety, anger, hostility, or alcohol abuse later in life. This is the largest prospective cohort study to date on this topic, and we controlled for a large number of baseline variables with our matching methodology.

Additionally, our long-term outcomes included sensitive performance-based measures of cognition and clinically validated measures of emotional function. Some may justifiably point out that, even after controlling for baseline variables, students who participated in high school athletics may differ in important and unobserved ways from those who didn’t. However, we found that considering a control group of subjects who played a non-contact high school sport did not materially change the results of our study.

Despite these strengths, there are important limitations to our work. Crucially, our findings may not generalize to current high school football players, as football has changed dramatically since the 1950s. Advances in helmet technology aimed at preventing catastrophic head injury may have had the unintended consequence of encouraging players to “lead with their heads,” increasing exposure to concussive and sub-concussive blows. Current athletes are bigger and faster and may be exposed to more powerful blows. Today’s player is probably more likely to enter high school with one or more prior head injuries, due to a trend towards young athletes “specializing” in football at younger ages and playing year-round. Pop Warner Little Scholars, the organizing body for youth football in America, has grown from a conference of 100 teams in 1947 to upwards of 5,000 teams nationally today.

While we did not find evidence of a large harmful effect of high school football on average, certain players may have an elevated risk of later-life dysfunction. For instance, the frequency and intensity of head impacts varies by position, with linemen estimated to sustain more than twice as many impacts per season as receivers (Broglio et al., 2011). Additionally, recent research highlights an association between the number of concussions and later-life dysfunction. We were unable to account for potential influences of position and concussion history in our study, as these data were not collected by the WLS.

The increasingly polarized discussion over the risks of football has made an honest reckoning of the emerging science difficult. While reports of CTE are concerning, research on CTE symptoms, in vivo diagnosis, progression, and treatment is in its infancy. Similarly, our study cannot be taken as irrefutable evidence of football’s safety. Football is unquestionably a risky sport, but it also promotes fitness, leadership and teamwork; our study found football players were more active at age 35 than non-football players. More research is needed to understand the tradeoffs between these risks and benefits. We hope our study, despite its limitations, can serve as a roadmap for future research. To this end, we are planning to replicate our study in a younger cohort with more detailed information on players’ positions and concussion history.

Though there is still no definitive study on the risks of playing football, there are several common-sense guidelines that can be followed today, like implementing measures that decrease the likelihood of concussions. Every concussion should be taken seriously, and increased awareness has led to vast improvements in sports-concussion management, with most interscholastic athletic programs following “return-to-play” protocols under physician supervision (now legally mandated in all states). Although it is too early to tell, there is hope that improved management will decrease risks of later-life impairment in vulnerable individuals.

As public awareness of the potential long-term consequences of playing football continues to rise, it is important to acknowledge that cognitive and emotional problems in former athletes are not always necessarily signs of CTE. Effective treatments are available regardless of etiology and those experiencing problems should seek help from a mental health professional.

The views expressed are those of the author(s) and are not necessarily those of Scientific American.

ABOUT THE AUTHOR(S)

Sameer Deshpande is a Ph.D. candidate in the Department of Statistics at the Wharton School at the University of Pennsylvania.

Raiden Hasegawa

Raiden Hasegawa is a Ph.D. candidate in the Department of Statistics at the Wharton School at the University of Pennsylvania.

Christina Master

Christina Master is professor of clinical pediatrics at the University of Pennsylvania Perelman School of Medicine and co-founding director of the Minds Matter Concussion Program at The Children's Hospital of Philadelphia.

Amanda Rabinowitz

Amanda Rabinowitz is a research assistant professor of rehabilitation medicine at the Sidney Kimmel Medical College of Thomas Jefferson University and Director of the Brain Injury Neuropsychology Research Laboratory at Moss Rehabilitation Research Institute.

Dylan Small

Dylan Small is Class of 1965 Wharton Professor of Statistics in the Department of Statistics at the Wharton School of the University of Pennsylvania.

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